Control research of NPC three level high-power grid connected inverter based on multi sampling

The influence of PWM control delay on the control stability of LCL grid connected inverter is analyzed. The advantages of multi sampling PWM control strategy are studied and pointed out. The problem of pulse loss and multiple comparison in the PWM modulation process is pointed out, and the solution of active damping control is given. The simulation verification is carried out using Matlab/Simulink. The simulation results show that, the multi sampling PWM control strategy can effectively solve the contradiction between low switching frequency of high-power grid connected inverter and PWM control delay, and effectively restraining the resonant peak of the LCL filter. It can improve the stability and dynamic response of the system, and realize the high performance control of active damping.